The researchers on the EDEN ISS project have developed a new design concept for a space greenhouse. This greenhouse is designed to be launched using a Falcon 9 rocket and can be deployed to provide sufficient space on the Moon or Mars to provide food for the astronauts. The area under cultivation would be approximately 30 square metres.

268 kilograms of food produced in an area of only 12.5 square metres over 9.5 months.

Power consumption less than half as much as previously assumed for greenhouses in space.

Concept – a deployable greenhouse suitable for launch on a Falcon 9 rocket.

Project in Antarctica continues.

Focus: Space, biosystems

Future food production in deserts and cold regions, as well as under the inhospitable conditions of future space missions to the Moon and Mars, is providing the stimulus for research in the Antarctic greenhouse project EDEN ISS, which is led by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR). DLR researcher Paul Zabel spent one year on the perpetual ice cultivating vegetables under artificial light and without soil. He was there as a member of the overwintering crew at the Alfred Wegener Institute'sNeumayer III Antarctic research station, in order to test cultivation processes under conditions that are hostile for plants and humans. On 23 August 2019, the EDEN ISS team presented the results of the project. The researchers were surprised that they managed with much less energy than expected and yielded such a large harvest, which clearly strengthened the well-being and mood of the overwintering team. But the workload required to maintain and support the system must be reduced significantly in order to save valuable time for astronauts in the future. The operation of the Antarctic greenhouse is currently ongoing and is open to research groups across the globe. From the results and experiences of the EDEN ISS project, a new greenhouse concept for the Moon and Mars has emerged – deployable, compact and suitable for launch using a Falcon 9 rocket.

"Future, long-term crewed space missions will require locally grown food. EDEN ISS has proven the feasibility of a space greenhouse in the Antarctic and thus demonstrated that this technology could also be used to produce food on the Moon and Mars," says Hansjörg Dittus, DLR Executive Board Member for Space Research and Technology. "The space greenhouse concept now being presented is a valuable foundation on which we wish to develop further research work."

Enough food for a crew of six

"Over a period of one year in the Antarctic, our greenhouse has clearly demonstrated that enough food can be generated in a small space to supplement the diet of a future six-person crew with about one third of freshly grown produce," says EDEN ISS project leader Daniel Schubert from the DLR Institute of Space Systems. This is a sensible supplement to the staple foods that the spacecraft will have brought with it from Earth. "Overall, we have produced 268 kilograms of food in an area of only 12.5 square metres over 9.5 months, including 67 kilograms of cucumbers, 117 kilograms of lettuce and 50 kilograms of tomatoes," says Zabel. "The taste and smell of fresh vegetables have left a lasting impression on the overwintering crew, and have clearly had a positive effect on the team's mood over the long period of isolation." This correlation is also being researched from a psychological perspective.

The frozen Antarctic continent is one of the world's most exciting regions for researchers. "The data we acquire there is primarily about global climate changes as well as the biodiversity of the Antarctic region. The greenhouse is an outstanding example of how we can also conduct research into other important forward-looking issues at the Neumayer III station. After all, the ability to explore regions that are hostile to human life brings us closer to human spaceflight. At the same time, the steady supply of fresh fruit and vegetables has once again had a very positive secondary effect on our overwintering crew," says Antje Boetius, Director of the Alfred Wegener Institute, who was able to enjoy a large, juicy radish grown in the greenhouse during her own stay at the station. “The cultivation of vegetables is also of great interest for future missions of the 'Polarstern' research icebreaker," she adds.

The power consumption of the greenhouse during the Antarctic analogue mission averaged 0.8 kilowatts per square metre of cultivation area and was therefore less than half the previously assumed amount for space greenhouses – 2.1 kilowatts per square metre. "This is an important aspect for space operations and makes us confident about the future of this idea," Schubert says.

Zabel needed an average of three to four hours per day to grow the plants. "The operation and maintenance of the greenhouse technology occupied about two-thirds of the time. The remaining third was needed for sowing, harvesting and plant care. For a future space greenhouse, the workload must be significantly reduced to save the valuable time of the astronauts." In addition, about four to five hours per day were needed for experiments. The aeroponic cultivation system – using artificial light, effective nutrient solutions and completely without soil – allowed the plants to thrive. Some pumps caused trouble intermittently and the biofilms in the nutrient tanks were unexpectedly strong, but this was corrected.

New greenhouse concept for the Moon and Mars

As a result, the scientists on the EDEN ISS project have now drafted a new design concept for a space greenhouse. This greenhouse is designed to be launched using a Falcon 9 rocket. Its deployable structure will provide astronauts with the necessary space to grow food on the Moon or Mars. "The cultivation space will amount to about 30 square metres and is therefore almost three times as large as the area used in the Antarctic greenhouse container. This system would allow approximately 90 kilograms of fresh food to be cultivated per month, which corresponds to half a kilogram of fresh vegetables per day for each astronaut in a six-member crew," Schubert explains.

The concept can also be combined with a biofilter system (C.R.O.P.), whose purpose is to treat biodegradable waste and urine in order to produce a ready-to-use fertiliser solution for plant cultivation. This would make the greenhouse concept an almost completely bioregenerative life-support system for future habitats on the Moon. This concept is the basis for further research.

Awakened by remote control

Upon Zabel's return to Germany, the Antarctic greenhouse was initially placed in 'sleep mode'. This was done following maintenance work by the DLR team on all systems in January 2019. The container was completely overhauled. In early May, the researchers in Bremen roused the system from its sleep by remote control and it started up. A previously introduced sowing began to thrive. "This step was used to test another spaceflight scenario in which a potential greenhouse arrives before the astronauts and operations are initiated by remote control," Schubert says. "The test run was a complete success. Now, the current AWI overwintering crew is continuing the operation of the greenhouse, with strong support from the control centre in Bremen, where we monitor as much as possible from a distance. The procedures developed last year are currently proving their worth in minimising the crew’s workload and keeping the processes as simple as possible."

NASA sends lettuce seeds

The EDEN ISS greenhouse is also open to other research groups worldwide that wish to carry out plant cultivation experiments in the Antarctic. "As one of the first new collaborative partners, NASA has sent us lettuce seeds. These seeds, which are also being cultivated on the International Space Station, are now thriving at our Antarctic station," adds Schubert.

EDEN ISS – food supply of the future

Global food production is one of the key societal challenges of the 21st century. An increasing world population and the simultaneous upheavals caused by climate change call for new ways of crop cultivation – even in regions with unfavourable climatic conditions. For deserts and areas with low temperatures, as well as for missions to the Moon and Mars, a closed greenhouse enables harvests that are independent of weather, sun and season, as well as lower water consumption and eliminates the need for pesticides and insecticides. As part of the EDEN ISS project, such a greenhouse of the future is being subjected to long-term testing under the extreme conditions found in Antarctica.